1. Field of the Invention
The invention, in general, is in the field of hybrid automobile air conditioning systems which derive energy from the waste heat of the engine and which have been proposed in the literature for reducing fuel consumption and, in particular, in the fields of control systems and thermal compression means for improving the fuel savings with such automobile air conditioners.
The invention relates also to a new control system for disabling an engine-driven mechanical compressor which is employed for initially precooling the automobile interior before switching to a thermal powered refrigeration system, which operates in a refrigerant flow path which goes around the refrigerant flow path of the mechanical compressor.
The invention further relates to an improved double vortex chamber flow inducer used as a thermal compression means n a thermally powered compression circuit, in which the power for the circuit is derived from the waste heat from the coolant of the internal combustion engine.
The invention also relates to a more compact ejector which provides efficient cooling to permit significant fuel savings in the operation of an internal combustion engine and cooling the interior of an automobile or similar vehicle powered by the engine.
2. The Prior Art
R. W. Murphy disclosed in the article entitled: "Estimated Fuel Savings for Heat Pump Systems That Combine Ejectors and Engine Driven Compressors" presented at the ASME Winter Annual Meeting Boston Mass. Dec. 13-18, 1987 and reprinted as Publication Number 87-WA/AES-4 a hybrid system of an engine-driven compressor and an ejector heat pump. This hybrid system permits savings in power calculated at only 19% for a parallel circuit and only 11% savings for a series circuit, an ejector using the waste heat being in one circuit and an engine-driven compressor being in the other circuit. The calculations constitute the major contribution of the article. The problem of low percentage of energy savings is solved by the present invention which realizes a much greater savings. The circuit described by Murphy has no means of preventing parasitic recirculation of refrigerant flow through the thermal compression means which the present invention prevents.
Ophir et al., U.S. Pat. No. 3,922,877 shows the diversion of waste heat from the radiator liquid coolant of an automobile for powering an air conditioner in a system using an ejector to drive refrigerant waste toward an air cooled condenser. This system cannot perform cooling until the engine coolant is sufficiently heated. The present invention provides an instant "ON" as expected by passengers and as now provided.
Chen, in the article entitled "A Heat Driven Mobile Refrigeration Cycle Analysis" in Energy Conversion, Vol. 18, pages 25-29, Pergamon Press Ltd., 1978, Great Britain, optimistically describes a thermal compressor for mobile use utilizing engine waste heat for a 2000 cc automobile producing 2.34 tons of cooling effect while the power consumption was just 0.06 H.P. The system in his FIG. 4 includes a regenerator between the ejector and the air condenser and thus comprises a modification for this regenerator feature with respect to the Ophir et al patent. Chen also must delay operation until engine coolant is hot enough and has no back-up in case the refrigerant pump fails.
Fineblum, the present inventor, in a paper entitled "Vortex Diodes" presented at the Fluidic State Of The Art Symposium, Sept. 30-Oct.3, 1974, Vol. 1, pages 48 through 89, describes a method for predicting and improving the pressure drop efficiency of a vortex chamber which is incorporated in the expansion portion of improved double vortex chamber thermal compression means as taught herein.
Modisette, U.S. Pat. No. 4,378,681, granted Apr. 5, 1983, discloses a double vortex chamber thermal compression means with a swirling expansion chamber device in a cooling circuit in which the high pressure refrigerant vapor enters the vortex expansion chamber and then passes into a diffuser chamber. The chambers are of a shape to generate excessive boundary layer related flow restriction and energy loss, which the present invention avoids. In addition, Modisette shows no back-up provisions while the present invention does.
J. C. Dutton and B. F. Carroll in the paper entitled "Optimal Supersonic Ejector Designs" published in the Transactions of ASME Journal of Fluids Engineering, Vol. 108, December 1986, disclose that the mixing section in an ejector should have a flow area which is twice the flow area of the primary nozzle in order to achieve optimum performance.
In an article by B. M. Agrow and G. Emanuel entitled "Comparison of Minimum Length Nozzles" published in the Journal of Fluids Engineering, September 1988, there is disclosed the teaching that the diffuser section of nozzles should expand in a gentle curve. The present invention combines these findings synergistically into a more efficient and compact ejector.
Lofgreen et al., U.S. Pat. No. 3,470,707 dated Oct. 7, 1969, discloses an automobile refrigeration system utilizing the waste heat from the exhaust manifold of an automobile engine. The apparatus in this patent requires pumps to pump the vapor and the liquid refrigerant separately and further requires a separator to separate the liquid from the vapor from the evaporator. The waste heat from the engine is used merely to heat the liquid and the separation requirement helps the system by reducing the energy required for the vapor pump but these features are significantly different from those in the present invention.
Trumpler, U.S. Pat. No. 2,411,347 discloses a turbine pump in combination with a compressor together with a boiler 14 connected to the compressor for cooling in an air conditioner for an automobile or for a railroad car. The compressor 16, which is used by Trumpler is driven by what is called a wobble plate engine. A control is provided in a refrigeration circuit in the form of an evaporation expansion valve and this control serves to direct the flow of the refrigerant to either the boiler or to the evaporator. The extra complexity and cost of such equipment and lack of instant "ON" are avoided by the present invention.
Dasher, U.S. Pat. No. 2,532,012 shows a cooling system in an automobile utilizing a rotary gas motor, a compressor, and switches controlled by pressure which develops in the receiver. A valve is provided in this system to utilize the waste heat from the exhaust. The control switch for the motor pump compressor is controlled by the pressure in the receiver. This system has no back-up, no instant "ON" and may interfere with the pollution control features of contemporary exhaust systems.
Rogers, U.S. Pat. No. 2,991,632 discloses an automobile air conditioner using waste heat of the engine as a source of heat powered refrigeration. A boiler for the refrigerant furnishes superheated vapor to drive the hot gas motor which drives the compressor. The engine compressor and pump are all constructed in a sealed unit. The mechanical devices are of greater complexity and cost with no significantly greater efficiency than thermal compression means and no back-up in case of failure while the present invention is mechanically simpler and has a back-up feature for improved reliability.
P. B. Keller, U.S. Pat. No. 2,869,332 shows a refrigeration system powered by the waste heat of an engine used to boil liquid refrigerant and the resultant vapor is separated from the remaining liquid and used to drive a turbine which drives a refrigeration compressor through a speed reduction gear box. The system requires the complexity of a high speed turbine and a reductor gear box which is very expensive and cannot begin to function until the engine coolant is hot enough and has no back-up for the waste heat powered system, which the present invention has, along with greater simplicity and concomitant reduced first cost and reliability.
E. P. Volchkov et al. in a 1982 paper "Hydrodynamics of a Vortex Chamber with Hyperbolic End Covers," FLUID MECHANICS Soviet Research, Vol. 11, No. 6 November-December 1982, 1984 Translation-Scripta Publishing, demonstrated that the boundary effects were weak and that the circulation in the vortex chamber had no significant losses compared to ideal free vortex flow if the vortex chamber was expanded toward the central axis in a manner which is approximately hyperbolic, that is, the axial dimension increases as the radius decreases; xr=constant where x is the axial dimension and r is the vortex chamber radius.
C. Rodgers in an ASME publication, "The Performance of Centrifugal Channel Diffusers" ASME 82-GT-10, shows that optimum pressure recovery is achieved in the diffuser channel of a centrifugal compressor if the velocity from the whirling impeller is decreased by 45 to 50% before it reaches the diffuser vanes.